1. Field of the Invention
This invention relates to a hinge and counterbalance assembly for pivotally mounting a lateral end of a vehicle tailgate at a lower extremity thereof for movement of the tailgate on an associated vehicle between an upper closed position and a lower open position and for also providing counterbalancing of the tailgate during a portion of such movement.
2. Background Art
Vehicle tailgates for trucks or other passenger vehicles have previously included counterbalance and hinge mechanisms for mounting the lower extremity of a tailgate at opposite lateral ends thereof for movement between an upper open position and a lower closed position as well as providing counterbalancing during movement between these positions. As disclosed by U.S. Pat. Nos. 5,358,301 Konchan et al. and U.S. Pat. No. 5,988,724 Wolda, the hinge utilized can also cooperate with another associated hinge to permit removal of the tailgate, which is often done with the tailgate midway between its open and closed positions, where a stationary hinge member on the vehicle has a slot that permits withdrawal of a pivotal tongue type hinge member on the tailgate by upward and rearward movement of the tailgate and then lateral movement to release the tailgate at a hinge adjacent its other lateral end.
Vehicles, of course, have also included other rear gates such as lift gates as disclosed by U.S. Pat. No. 5,960,519 Thompson et al., which is assigned to the assignee of the present application, where a hinge and counterbalance assembly provides counterbalancing during the final portion of opening movement.
Other prior art references noted during an investigation conducted in connection with the present invention include U.S. Pat. Nos. 2,984,517Farrow et al.; U.S. Pat. No. 3,031,225 Saffer et al.; U.S. Pat. No. 3,336,070 Jackson; U.S. Pat. No. 3,643,378 Velavicius et al; U.S. Pat. No. 4,143,904 Cooper et al.; U.S. Pat. No. 4,580,315 Beckwith; and U.S. Pat. No. 5,771,540 Carpenter et al.
An object of the present invention is to provide an improved vehicle tailgate hinge and counterbalance assembly.
In carrying out the above object, the vehicle tailgate hinge and counterbalance assembly pivotally mounts a lateral end of a vehicle tailgate at a lower extremity thereof for movement of the tailgate on an associated vehicle between an upper closed position and a lower open position and the assembly also provides counterbalancing of the tailgate. The assembly includes a hinge having a first hinge member for mounting on the tailgate and also has a second hinge member for mounting on the vehicle. A pivotal connection pivotally connects the hinge members to support the tailgate for movement about a pivotal axis between the closed and open positions. A torsion rod of the assembly has an intermediate portion that extends within the tailgate laterally inward from the hinge. An inner end of the torsion rod extends transversely from the intermediate portion thereof within the tailgate and has a distal end portion. An outer end of the torsion rod is located outwardly of the tailgate adjacent the hinge and extends transversely from the intermediate portion terminating in a distal end portion. Within the tailgate, a tailgate brace of the assembly engages the distal end portion of the inner end of the torsion rod to limit rotation of the torsion rod during opening and closing movement of the tailgate. The first hinge member of the hinge has a positioner that positions the intermediate portion of the torsion rod spaced from the pivotal connection of the hinge, and the outer end of the torsion rod extends from the positioner of the first hinge member around the pivotal connection of the hinge to its distal end portion. The second hinge member of the hinge has an engagement portion that is spaced from the distal end portion of the outer end of the torsion rod when the tailgate is in its closed position, and the engagement portion is engaged by the distal end portion of the outer end of the torsion rod after the tailgate has moved toward its open position to provide counterbalance of the tailgate during movement between a partial open position and the open position.
In its preferred construction, the hinge and counterbalance assembly includes a tailgate brace having an elongated member which includes a first end having a pair of oppositely extending mounting flanges for attachment to the tailgate adjacent its lower extremity. A second end of the brace has a mounting flange for attachment to the tailgate at a remote location from its lower extremity. An intermediate portion of the brace extends between its first and second ends with a U-shaped cross section in which the distal end portion of the inner end of the torsion rod is engaged with the brace to limit the rotation of the torsion rod. The tailgate brace also includes a positioner that engages and locates the intermediate portion of the torsion rod on the opposite side of the first end of the elongated brace member from the second end of the brace member. The positioner of the tailgate brace is secured to one side of one of the mounting flanges of the first end of the elongated brace member. An attachment plate of the tailgate brace is secured to the other side of the one mounting flange of the first end of the elongated brace member and is also secured to the other mounting flange of the first end of the elongated brace member with the inner end of the torsion rod located between the brace member and the attachment plate within the U-shaped cross section of the brace member. More specifically, the attachment plate has opposite ends that are respectively secured to the pair of mounting flanges of the first end of the brace member, and the attachment plate also has a curved intermediate portion that connects its opposite ends and extends around the inner end of the torsion rod.
The assembly has the pivotal connection of the hinge constructed to include first and second annular connection portions respectively mounted by the first and second hinge members with one of the annular connection portions received within the other one and with the pivotal axis centrally extending through the annular connection portions. An annular bearing is located between the first and second annular connection portions, and the outer end of the torsion rod extends from the positioner of the first member to its distal end portion in a generally diametrically opposite location with respect to the annular connection portions through which the pivotal axis extends.
The construction of the first hinge member of the hinge includes a plate that is secured to the tailgate and also includes an annular connection portion that is secured to its plate extending therefrom, and the plate of the first hinge member supports its torsion rod positioner. The second hinge member includes a plate that is secured to the vehicle and also includes an annular connection portion that is secured to its plate extending therefrom. One of the annular connection portions is received within the other annular connection portion, and an annular bearing is located between the annular connection portions with the pivotal axis extending therethrough. The outer end of the torsion rod extends from the positioner of the first hinge member to its distal end in a generally diametrically opposite location with respect to the annular connection portions through which the pivotal axis extends. The annular bearing is made from plastic and has one axial end secured to the plate of one of the hinge member. Furthermore, the plate of the first hinge member includes a hook that embodies the torsion rod positioner for positioning the torsion rod adjacent its outer end.
The plate of the second hinge member of the hinge includes an annular engagement flange that embodies the engagement portion which is spaced from the distal end of the outer end of the torsion rod when the tailgate is in its closed position and which is engaged by the distal end of the outer end of the torsion rod after the tailgate has moved toward its open position to provide counterbalancing of the tailgate upon further movement toward the open position. This engagement flange of the plate of the second hinge member includes a wear pad shaped as a sleeve that receives the engagement flange for mounting.